Dump valve not closing

[Mycornfarm]

Thanks for allowing me to join, I have a dump valve question. My black water tank dump valve does not seem to be closing. The valve is enclosed with the tank and out of sight, 2002 Thor Fifth Ave 5th wheel. How can I get access to the dump valve? I suspect the cable is loose but can’t be sure. Jack

 

[redbaron]

Most likely the cable has a bend that does not allow a full push or pull on the valve.

These cables are similar to the ones on a bicycle hand brake.

Try to pull the cable out (pulling slack) towards bottom, so the excess is outside the corplast, then see if it moves.

Otherwise you will have to remove the corplast bottom to gain access to the valves.

On my trailer, I replaced the cable with a shorter length to fix the problem.

 

[Mycornfarm]

Is the corplast underneath the trailer?

 

[redbaron]

Yes. It's the bottom layer that's plastic cardboard